1. Field of the Invention
The present invention relates to an ink jet recording head and an ink jet recording device that jet an ink droplet on a recording medium to form an image.
2. Description of the Related Art
Recently, an ink jet recording device is drawing attention as a low-cost, quality color recording device. For an ink jet recording head of an ink jet recording device, there are known a piezoelectric type of ink jet recording head that jets ink from a nozzle by pressure generated by mechanically deforming a pressure chamber with a piezoelectric material for example and a thermal ink jet recording head that jets ink from a nozzle with pressure acquired by energizing a heater element arranged in an individual passage and vaporizing ink.
In these ink jet recording heads, a head chip in which an ink jetting mechanism that jets an ink droplet is installed is joined to an end of an ink supply member. Concretely, ink is supplied to an ink supply port provided to the head chip from a pipeline of the ink supply member and is jetted from a nozzle.
In an ink jet recording head related to prior art, since the sealing performance of the contact surface cannot be secured only by combining a head chip and an ink supply member, the head chip and the ink supply member are bonded using an adhesive as disclosed in Japanese Published Unexamined Patent Application No. Hei 5-38812 (hereinafter called conventional example 1) for example to secure the sealing performance of the contact surface.
Also, for an ink jet recording head in which an ink supply member and a head chip are joined without using an adhesive, a junction of the head chip and the ink supply member is made of an organic member and they are joined by ultrasonic fusion as disclosed in Japanese Published Unexamined Patent Application No. Hei 8-230191(hereinafter called conventional example 2).
Further, for another example, there is an ink jet recording head in which a head chip and an ink supply member are integrated by hot riveting as disclosed in Japanese Published Unexamined Patent Application No. Hei 4-251748 (hereinafter called conventional example 3).
In the conventional example 1, the applied amount and the applied position of an adhesive are required to be strictly managed so that the adhesive is not forced out from the contact surface to a pipeline of the ink supply member and an ink supply port of the head chip or to a nozzle formation surface of the head chip. Therefore, the intricate control of a high accuracy coater, the applied position and the applied amount are required and the cost of the ink jet recording head is increased.
Also, as the coefficients of thermal expansion of the head chip, the ink supply member and the adhesive are different, a crack in the head chip and peeling on the contact surface are caused by thermal stress caused by a heating process in the assembly of the ink jet recording head and the yield in the manufacture of the ink jet recording head is deteriorated.
Also in a method related to the conventional example 2 and the conventional example 3, as the ink supply member and the head chip are heated by ultrasonic fusion and hot riveting, a similar problem due to thermal stress occurs.
Further, in the conventional examples 1 to 3, the ink supply member and the head chip are deformed by heating in joining and ink jetting performance may be deteriorated.
Also, there is a problem that it is difficult to disassemble the inkjet recording head once assembled in any of the conventional examples 1 to 3 and it is difficult to fractionalize every part different in materials for recycling.
The present invention has been made to solve the problems and provides an ink jet recording head in which a head chip and an ink supply member are precisely joined and an ink jet recording device.
According to an aspect of the present invention, the ink jet recording head includes a head chip in which an ink jetting mechanism for jetting an ink droplet is installed and to which an ink supply port for supplying ink from the outside is supplied, an ink supply member to which a pipeline for supplying ink to the ink supply port is provided and an elastic member which is provided between the ink supply member and the head chip and which seals a connection of the ink supply port and the pipeline by being pressed upon the ink supply member and the head chip.
The pipeline and the ink supply port are connected with a connection securing sealing performance by inserting the elastic member between the head chip and the ink supply member and pressing it upon both. Therefore, an adhesive and others difficult to handle in the assembly of the head are not required and the head can be easily manufactured. Also, as heating is not required for assembly, deformation of the head chip and the ink supply member by heating to cause peeling of the head chip and the ink supply member as well as a negative effect upon the jetting performance of the ink jet recording head are not caused. Particularly, since a difference in deformation among each member is absorbed by deformation of the elastic member even if the coefficient of thermal expansion of each member is different, satisfactory sealing performance of a connection can be secured.
Further, since only the elastic member is inserted between the ink supply member and the head chip, the ink jet recording head can be disassembled into each part and fractionation in recycling is facilitated.
The ink jet recording head may include a regulator that regulates a deformed amount by pressure of the elastic member.
The ink jet recording head may also include a holding member to which the head chip is fixed, and the regulator may be formed in at least one of the ink supply member and the holding member, and it may come into contact with the other member as a contacting part in assembly.
The holding member may also include a guide unit that guides the ink supply member, when the ink supply port is open in the two directions, so that the elastic member is pressed upon the head chip from an intermediate direction of the two directions.
At least two of the head chip, the ink supply member and the holding member may be different in a coefficient of thermal expansion.
The elastic member and the ink supply member may be fabricated and integrated by insertion molding.
According to another aspect of the present invention, the ink jet recording head includes a head chip formed by laminating silicon substrates and provided with a nozzle, an individual passage for supplying ink to the nozzle and a common liquid chamber for supplying ink to plural individual passages, an ink supply member a wall of which is formed next to a wall of the head chip forming the common liquid chamber and which is provided with an ink chamber integrated with the common liquid chamber and an elastic member which is inserted between the head chip and the ink supply member and which seals a connection of the ink chamber and the common liquid chamber.
As the common liquid chamber is substantially large-sized by integrating the common liquid chamber provided to the head chip and the ink chamber provided to the ink supply member, bubbles generated in the common liquid chamber are moved to positions apart from the individual passages. As a result, bubbles can be prevented from blocking the individual passages and lowering ink jetting performance.
Also, since the wall forming the common liquid chamber and the wall forming the ink chamber are formed next to each other, sealing performance by the elastic member becomes satisfactory.